In addition to the large number of infecting fungal diseases plants are also subject to damages caused by various phytopatogenic bacteria.
The most important characteristics of the diseases induced by plant patogenic bacteria are summarized by Klement [Plant Protection (1982) No. 3].
______________________________________ Bacterial material responsible for the Symptom group Pest symptoms ______________________________________ Necrosis stain- Pseudmonas Bacterial polysaccharides. diseases Materials inducing necrosis Cancerous Xanthomonas Chlorogenic toxins, growth, wilting Necrogenic toxins withering Coryne- Cellulose decomposing enzymes; bacterium toxins causing withering Soft rot Erwinia Pectin decomposing enzymes Tumors Agrobacterium Information material coded by plasmids ______________________________________
From the group of phytopatogenic bacteria the species which infect the propagating materials--seeds, tubers, bulbs, tree-nursery propagating materials--are particularly significant. Thus Corynebacterium michiganense on tomato and Corynebacterium nebraskaense on maize can be mentioned. Agrobacterium tumefactiens induces large tumors on the propagating materials of various fruit-species and vine and makes the infected material unsuitable for use. From the phytopatogenic bacteria Erwinia species causing soft rot on stored crops having a high liquid and juice content and that of propagating materials (tubers, bulbs, onion-roots) are particularly harmful because of the significant economic damage caused.
Erwinia carotovora var. atroseptica is responsible for the soft rot of potato during storage and in the absence of effective protection the damages caused may be particularly significant.
According to Pinter [Plant Protection "Novenyvedelem" (1982) No. 3] in the case of a soft rot of 5% the damage appearing on potato may be estimated to a sum higher than 100 million forints.
In prior art the significance of the simultaneous appearance of bacterial (Erwinia carotovora var. atroseptica) and fungal diseases is discussed in detail [see e.g. Stachewich: 1974., Nachr. Blatt Pflschutz., 28. (2)., Wellving: Sweed. Seed. Assoc. (31); Anonym: Merkbl. des Pflschutz, 1974, (10)].
Thus potato may be simultaneously attacked by fungal and bacterial diseases both during storage and after sowing.
Pesticidal active ingredients used against simultaneously occuring fungal and bacterial diseases are summarized in Table 1, where the prior art citations are disclosed as well.
TABLE 1 __________________________________________________________________________ Pest Active ingredient Citation __________________________________________________________________________ Erwinia carotovora phenyl-alanine, Gupta, Tripathi var. atroseptica ammonialiase, poly- Indian J.E. 1976. phenol 4. [3.] streptomycin, Albergiana, kanalicin, neomycin, Phytopath. Zeit. erithromycin, 81. [2.] chloramphenicol Fusarium Benomyl Leach, 1975 USDA 17. Jellis, Taylor Ann. Appl. Biol. thiabendazol Munzel, Bayer Land. 1976. 52. [2.] Erwinia MBC + chloramphenicol, Ratba, Spez. carotovora var. Pflsch. 1977. 1. atr. + Fusarium benomyl + chloram- Burth, Jahn phenicol, Zineb + Akad. Landw. Wiss. + chloramphenicol [140] Zineb + chloram- Anonymus, Gops. phenicol Soil. 1975. 30. [1.] Erwinia + antibiotic + Sahurai, 1975. Pseudomonas fungicide J. Antibiotics, 29. [11.] __________________________________________________________________________
However, none of the above compositions is suitable for complete protection and therefore antibiotics are used for the control of bacterial infection. In most of the countries however, the use of antibiotics in agriculture is prohibited.